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Wednesday, February 6, 2013

NASA: Asteroid Will Not Hit Earth

The small near-Earth asteroid, 2012 DA14, will pass very close to Earth on
February 15, 2013, so close that it will pass inside the ring of
geosynchronous weather and communications satellites.

NASA says its Near-Earth
Object Program Office can accurately predict the asteroid's path with
the observations obtained, and it is therefore known that there is no
chance that the asteroid might be on a collision course with Earth.

Nevertheless, the flyby will provide a unique opportunity for
researchers to study a near-Earth object up close. Here are the facts
about the safe flyby of Earth of asteroid 2012 DA14 -- a record close
approach for a known object of this size.

NASA issued the following Questions and Answers about the asteriod near miss with Earth:

Q: What is asteroid DA14

A: Asteroid 2012 DA14 is a small near-Earth object –
approximately 150 feet (45 meters) in diameter. On Feb. 15, 2013, the
asteroid will pass by our planet at a remarkably close distance, but the
asteroid’s path is understood well enough that there is no chance of a
collision with the Earth.

Q: What date and what time will the asteroid be closest to Earth?

A: Asteroid 2012 DA14 will be closest to Earth on Feb. 15 at
approximately 19:24 UTC (2:24 p.m. EST/11:24 a.m. PST). This time may
change by a minute or two as the asteroid is tracked on its approach and
predictions are refined.
At the time of closest approach, the asteroid will be over the eastern
Indian Ocean, off Sumatra -- approx. latitude: -6 deg South. /
longitude: 97.5 deg East.

Q: How far away will asteroid 2012 DA14 be at time of closest approach?

A: Asteroid 2012 DA14 will be only about 17,200 miles (27,700
kilometers) above Earth's surface at the time of closest approach on Feb
15, 2013. This distance is well outside Earth's atmosphere, but it is
inside the belt of satellites in geostationary orbit, which is located
22,200 miles (35,800 kilometers) above Earth’s surface. The
close-approach distance is only about one-tenth the distance between
Earth and moon. Another way to express the distance between asteroid and
Earth at time of closest approach is 4.4 Earth radii from Earth’s
surface – or about twice the diameter of the Earth.

Q: Could asteroid DA14 impact Earth?

A: No. The orbit of asteroid 2012 DA14 is well understood – it
will not come any closer than 17,150 miles (27,650 kilometers) above
Earth's surface during its flyby on Feb 15, 2013.
The asteroid’s orbit around the sun is roughly similar to that of Earth,
and it makes relatively close approaches to our planet’s orbit twice
per orbit. But, the 2013 flyby is by far the closest the asteroid will
approach our planet for many decades. The next notable close approach
to Earth will be on February 16, 2046, when the asteroid will pass no
closer than 620,000 miles (1,000,000,000 kilometers) from the
center-point of Earth.

Q: What makes 2012 DA14 special?

A: The flyby of asteroid 2012 DA14 is the closest ever predicted Earth approach for an object this large.

Q: How long will asteroid 2012 DA14 be within the Earth/moon system?

A: Asteroid 2012 DA14's will be within the Earth/moon system for
about 33 hours. Its orbit will bring it within the Earth/moon system
(approach within one lunar distance, 237,000 miles of the Earth) on Feb.
15 at about 0300 UTC (7 p.m. PST on Thursday, Feb. 14). The asteroid
will exit the Earth/moon system on Feb. 16 at about 1200 UTC (4 a.m.
PST).

Q: Is there a chance that asteroid 2012 DA14 could be eclipsed by Earth?

A: Because of its trajectory, there is no chance that asteroid 2012 DA14 will pass through Earth’s shadow.

Q: How big is asteroid 2012 DA14?

A: Asteroid 2012 DA14 is currently estimated to be about 150 feet
(45 meters) across and has an estimated mass of about 130,000 metric
tons. If radar observations of this asteroid are successful, we might
have a more accurate estimate of the asteroid’s size after its close
approach.

Q: How fast will the asteroid be traveling at closest approach?

A: Asteroid 2012 DA 14 is traveling at about 17,450 miles per
hour (28,100 kilometers per hour), or 4.8 miles per second (7.82
kilometers per second) relative to Earth.

Q: Who discovered asteroid DA14?

A: Asteroid 2012 DA14 was discovered by the La Sagra Sky Survey
operated by the Astronomical Observatory of Mallorca in Spain on Feb.
23, 2012. The asteroid was about 2.7 million miles (4.3 million
kilometers) distant when it was detected. Their observations were
reported to the NASA funded Minor Planet Center, operated by the
Smithsonian Astrophysical Observatory for the International Astronomical
Union, where all observations from observatories worldwide are combined
to maintain the database on all known asteroids and comets in our solar
system.

Q: How many asteroids are out there similar in size to asteroid DA14?

A: Scientists believe there are approximately 500,000 near-Earth
asteroids the size of 2012 DA14. Of those, less than one percent have
been discovered.

Q: How many times do asteroids the size of DA14 fly this close?

A: Scientists at NASA's Near-Earth Object Program Office in
Pasadena, Calif. estimate that an asteroid the size of 2012 DA14 flies
this close every 40 years on average and that one will impact Earth, on
average, about once in every 1,200 years.

Q: Is there a chance that asteroid DA14 will collide with one or more satellites?

A: There is very little chance that asteroid 2012 DA14 will
impact a satellite or spacecraft. Because the asteroid is approaching
from below Earth, it will pass between the outer constellation of
satellites located in geosynchronous orbit (22,245 miles/35,800
kilometers) and the large concentration of satellites orbiting much
closer to Earth. (The International Space Station, for example, orbits
at the close-in altitude of 240 miles/386 kilometers.). There are
almost no satellites orbiting at the distance at which the asteroid will
pass.

Q: What will asteroid DA14’s close pass do to Earth’s rotation/tides/fault lines/etc.

A: The gravitational influence upon Earth and its inhabitants by the flyby of asteroid 2012 DA14 will be infinitesimally small.

Q: What would happen if DA14 were to impact Earth?

A: Asteroid 2012 DA14 will not impact Earth, but if another
asteroid of a size similar to that of 2012 DA14 (about 150 feet across)
were to impact Earth, it would release approximately 2.5 megatons of
energy in the atmosphere and would be expected to cause regional
devastation.
A comparison to the impact potential of an asteroid the size of 2012
DA14 could be made to the impact of a near-Earth object that occurred in
1908 in Tuguska, Siberia. Known in the asteroid community as the
"Tunguska Event," this impact of an asteroid just slightly smaller than
2012 DA14 (approximately 100 – 130 feet/30-40 meters across) is believed
to have flattened about 750 square miles (1,200 square kilometers) of
forest in and around the Podkamennaya Tunguska River in what is now
Krasnoyarsk Krai, Russia.

Q: Can I see the asteroid during its close approach?

A: Asteroid 2012 DA14 is small, so even though it will make a
close flyby of Earth, the asteroid's apparent magnitude is expected to
peak at about only 7.4 – too dim to be viewed by the naked eye. To view
the asteroid, you will need a good pair of binoculars, or even better, a
moderately powered telescope.
During the closest approach, and dependant on local weather, the
asteroid will be visible from parts of Europe, Africa and Asia. The
asteroid will appear to be moving relatively quickly as it crosses the
sky from the south to the north.

Q: What is NASA doing about asteroid 2012 DA14?

A: As there is no chance of impact, there is nothing that needs
to be done about the asteroid. However, the flyby of 2012 DA14 is a
great opportunity for science. NASA's Goldstone Solar System Radar,
located in California's Mojave Desert, will observe the asteroid on Feb.
16, 18, 19 and 20. Due to the asteroid's small size, the radar images
generated are expected to be no more than a few pixels across. It will
also be observed by numerous optical observatories worldwide to attempt
to determine its spin rate and composition.

Q: What is NASA doing about Near-Earth Objects?

A: NASA has several ongoing programs regarding asteroid discovery and science.
The NASA Near Earth Object Observation (NEOO) Program detects and tracks
asteroids and comets passing close to Earth using both ground- and
space-based telescopes. The network of projects supported by this
program, commonly called "Spaceguard," discovers these objects,
characterizes a subset of them and plots their orbits to determine if
any could be potentially hazardous to our planet.
All observations from observatories worldwide are sent to the NASA
funded Minor Planet Center, operated by the Smithsonian Astrophysical
Observatory for the International Astronomical Union, where they are
combined to maintain the database on all known asteroids and comets in
our solar system. The Near-Earth Object Program Office at JPL manages
the technical and scientific activities for NASA's Near-Earth Object
Program of the Science Mission Directorate in Washington. JPL is a
division of the California Institute of Technology in Pasadena. The NEO
Program Office performs more precise orbit determination on the
objects, and predicts whether any will become an impact hazard to the
Earth, or any other planet in the solar system. The NEOO Program also
performs orbit analysis on the discovered Near Earth Asteroids (NEAs) at
Goddard Space Flight Center to determine which ones may become good
robotic or human spaceflight destinations in the near future.
NASA's 70-meter (230-foot) Goldstone antenna, located about 35 miles
north of Barstow on the Ft. Irwin Military Base, is part of NASA's Deep
Space network. The antenna is one of only two facilities capable of
imaging asteroids with radar. The other is the National Science
Foundation's 1,000-foot-diameter (305 meters) Arecibo Observatory in
Puerto Rico. The capabilities of the two instruments are complementary,
and NASA’s NEOO Program supports the radar capability at both these
facilities. The Arecibo radar is about 20 times more sensitive, can see
about one-third of the sky, and can detect asteroids about twice as far
away. Goldstone is fully steerable, can see about 80 percent of the
sky, can track objects several times longer per day, and can image
asteroids at finer spatial resolution. JPL manages the Goldstone Solar
System Radar and the Deep Space Network for NASA.
NASA has also started serveral basic research and technology
demonstration projects to better understand the nature of asteroids and
how they might best be deflected from an Earth impacting trajectory, or
to develop the space technology required to do this. This development
work includes improved Solar Electric Propulsion (SEP) systems that
could push or pull an asteroid for an extended time, and close proximity
operations and grappling mechanisms to work in and around asteroids and
manipulate their surfaces. This technology will also be useful for
future robotic and human missions to these objects, and even potentially
resource mining operations.